<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    td{
        width: 20px;
    }
</style>
<body>
    <table border="1"  style="border-collapse: collapse;" >
    <tr>
        <td colspan="12"  style="text-align: center;">1</td>
        <td rowspan="12">2</td>
    </tr>
    <tr>
        <td rowspan="12">4</td>
        <td colspan="10" style="text-align: center;">5</td>
        <td rowspan="10">6</td>
    </tr>
    <tr>
        <td rowspan="10">8</td>
        <td colspan="8" style="text-align: center;">9</td>
        <td rowspan="8">10</td>
    </tr>
    <tr>
        <td rowspan="8">12</td>
        <td colspan="6" style="text-align: center;">13</td>
        <td rowspan="6">14</td>
    </tr>
    <tr>
        <td rowspan="6">16</td>
        <td colspan="4" style="text-align: center;">17</td>
        <td rowspan="4">18</td>
    </tr>
    <tr>
        <td rowspan="4">20</td>
        <td colspan="2" style="text-align: center;">21</td>
        <td rowspan="2">22</td>
    </tr>
    <tr>
        <td rowspan="2">24</td>
        <td>25</td>
    </tr>
    <tr>
        <td colspan="2" style="text-align: center;">23</td>   
    </tr>
    <tr>
        <td colspan="4" style="text-align: center;">19</td>     
    </tr>
    <tr>
        <td colspan="6" style="text-align: center;">15</td>
    </tr>
    <tr>
        <td colspan="8" style="text-align: center;">11</td>
    </tr>
    <tr>
        <td colspan="10" style="text-align: center;">7</td>
    </tr>
    <tr>
        <td colspan="12" style="text-align: center;">3</td>
    </tr>
</table>
</body>
</html>